Plastic collapsible screw fastening device having auxiliary holding means



Nov. 5, 1963 A. DISLEY 42 PLASTIC COLLAPSIBLE SCREW FASTENING DEVICEHAVING AUXILIARY HOLDING MEANS Filed May 20, 1960 Inventor wsRE/ J)ISLEY g By AGE VT United States Patent M 3,109,342 PLASTIC COLLAPSlSL'ESa CREW FASTENlNG DE VICE HAVING AUXHLIARY HGLDENG MEANS Aubrey DisieKnowle, England, assigucr to George Goodman Limited, Birmingham,Warwick, England, a British company Filed May 20, 1%9, Ser. No. 39,593Claims priority, application Great Britain June 25, 1959 2 Claims. ((11.85-49) This invention relates to a screw fastening device of the kindcomprising a sleeve adapted to be mounted in a prepared hole in themember to which the fastening device is to be applied, said sleevehaving an enlarged head at one end and being so formed that when a screwis driven into the sleeve from this end, the wall of the sleeve which ison the side of said member remote from the head, is caused to bulgeoutwardly so that ultimately the sleeve is firmly anchored in the saidmember. Such screw fastening devices are hereinafter referred to asbeing of the kind specified.

Hitherto in this known kind of fastening device the sleeve made of metalhas been cylindrical throughout and when being used, the head is held bya tool whilst the screw is being driven to prevent rotation of thesleeve and to prevent the sleeve from being drawn out of the said memberdue to the axial pull which exists when the wall of the sleeve is beingbulged.

The object of the present invention is to provide an improved fasteningdevice of this kind which will be simpler to install than the kind knownhitherto and which also possesses other advantages as are referred tohereinafter.

According to the present invention, I provide a screw fastening deviceof the kind specified comprising a sleeve which is of generallycylindrical form over the major portion of its length and at one end hasa flange projecting radially outwards, the external surface of theportion of the sleeve which is immediately adjacent this flange, beingformed to a non-circular cross section so that the sleeve can be mountednon-rotatably in a member having a hole of such shape as to engagenon-rotatably with the said portion of the sleeve and with theunderneath of the flange of the sleeve engaging the surface of themember surrounding said hole, and the sleeve being further provided withone or more projections on or adjacent said portion of non-circularcross-section and spaced away from said flange, which projections areadapted to engage with said member when the sleeve is mounted inposition to prevent the sleeve from being withdrawn.

Preferably the projections are so formed and located on the sleeve that,when the sleeve is inserted, they engage the surface of the memberremote from the flanged end of the sleeve.

The member above referred to may, for example, be a single sheet orplate to which something is to be attached by means of a screw and asleeve in accordance with the invention, or in another case the membermay be two or more sheets which are to be secured together and thefastening device of the present invention is particularly advantageousin cases where one side of the said member is inaccessible. Hence thefastening device of the present invention is particularly useful as ablind side fastener.

I prefer to make the sleeve from a synthetic resinous material such, forexample, as a suitable form of nylon as this enables the sleeve to beeasily and economically produced by a die-casting operation and providesa sleeve wall which is readily bulged when a screw is applied and alsoin this material the aforesaid projections on the sleeve can be readilysprung through the opening in the member to which the sleeve is appliedand being resilient 3,139,342? Patented Nov. 5, 1963 will recover theirshape and provide the locking function on the blind side of the member.

Further advantages arising from producing the sleeve from syntheticresinous material are that, firstly, it provides a fastening with sounddeadening properties which is useful in cases where vibration isencountered and secondly it can be used in cases where electricalinsulation properties are required and after installation of the sleevethe screw used may be removed leaving a fixed insulating sleeve passingthrough a partition.

Conveniently the non-circular portion adjacent the flange on the sleeveis of square form and also to facilitate the use of the sleeve, theflange may also be of square form with its sides parallel to the sidesof the other square so that when this flange is held in the hand, thesquare portion of the sleeve can be readily orientated for installationinto a corresponding square hole provided in the sheet, plate, or othermember to which it is to be applied.

The internal passage in the sleeve may, if desired, be provided with ascrew thread but I prefer to leave a plain passage as this enables lessexpensive production and when the sleeve is made in synthetic resinousmaterial a screw can easily cut its own thread when applied.

The invention is illustrated in one embodiment in the accompanyingdrawings wherein:

FIGURE 1 is a section through the sleeve shown inserted in a hole andprior to the application of a screw.

FIGURE 2 is an underneath plan view on FIGURE 1.

FIGURE 3 is a view similar to FIGURE 1 but illustrating the deformationof the sleeve when a screw is applied.

FIGURE 4 is an enlarged fragmentary view of one of the projections.

FIGURE 5 is a section on the line 5-5 of FIGURE 4, and,

FIGURE 6 is a section on the line 66 of FIGURE 4.

In the embodiment of the invention shown in the drawings, the sleeve 14is made from a suitable grade of nylon and over the major portion of itslength is of generally cylindrical formation with. a slight taperprovided on the external surface at the end 11 of the sleeve remote fromthe flange 12 so as to provide a lead-in portion to assist in rapidinstallation of such sleeve into its prepared hole 13 in the member 14to which it is applied. At the other end, the sleeve has the outwardlyprojecting flange 12 which is of square form and immediately adjacentthis flange the external surface 15 of the sleeve, for a short portionof its length, is formed to square cross-section, the sides of thissquare 15 being parallel to the corresponding sides of the flange 12.

The square portion 15 of the sleeve is provided with two projectionsindicated at 16 in FIGURES 1-3 and shown in enlarged detail in FIGURES4-6.

As seen best in FIGURE 2, the projections 16 are situated at oppositecorners of the square 15, and (referring to FIGURES 4-6) each projectioncomprises a stem 17 extending from the underneath face of the square 15in a direction parallel to the axis of the sleeve and a nose '18projecting outwardly in a direction which is radial to the axis of thesleeve.

it will be observed that the stem 17 is spaced outwardly away from theouter wall of the sleeve and that the tip 19 of the nose 18 projectsoutwardly a greater distance from the axis of the sleeve than the cornerof the square portion 15. Thus the distance between the two tips 19 ofthe projections, is greater than the diagonal measurement of the hole 13in the member 14.

v The underside surface 24) of each nose 18 is inclined at an acuteangle to the axis of the sleeve so that these two surfaces 20 aremutually convergent in the direction towards the entry end ill of thesleeve. Further,

, through to the flanged end of the sleeve.

In use, the square hole 13 is provided in the plate, sheet, or othermember 14 to which the fastening is to be applied, this hole havingdimensions to correspond to the square portion 15 on the surface of thesleeve and then the sleeve is pushed through the hole so that theprojections 16 on the sleeve are deflected inwardly in passing throughthe hole 13 in the member 14 and then regain their original form and thenoses 18 engage the surface 24 of the member 14 remote from the flangeof the sleeve so that when in position the square portion 15 of thesleeve is engaged in the square hole 13 in the member and the sleeve isprevented from being Withdrawn by virtue of the noses of the projectionsengaging the member 14.

When a screw 25 is applied it cuts its own thread in the smallerdiameter portion 22 through the passage of the sleeve and after the headof the screw has made engagement with the flange 12 of the sleeve,further rotation of the screw will draw the tapered end 11 of the sleevetowards the flanged end causing the wall of the sleeve to bulgeoutwardly (see FIGURE 3) and finally reaching a position where theoutwardly bulged wail 26 makes contact with the surface 24 of the member14 remote from the flange, thus locking the sleeve firmly in position.

The projections 16 on the sleeve prevent any tendency for the sleeve towithdraw during this operation and rotation of the sleeve is preventedby virtue of its square portion 15 engaging in the square hole 13 in themember 14 so that no special tool is required for applying the fasteningand a conventional form of screw-driver may be used.

Further the screw may be taken out of the sleeve and reinserted asdesired without loss of eficiency of the fastening.

The disposition of the projections 16 at the opposed corners of thesquare 15 has the added advantage that it assists in the initialinsertion of the sleeve as it is found that as the sleeve is pushed intothe hole 13 and given a slight angular movement the projections 16 willlocate themselves at the corners of the square hole and thus greatlyfacilitate the operation of lining up the square portion 15 with thesquare hole 13. The sloping surfaces 13 give a lead-in to assist theprojections in entering the hole 13.

The form of projections 16 shown in the drawings has af-u-rtheradvantage in practice because, although the length of the stem 17 of theprojection is chosen 7 to suit the thickness of sheet 14 with which itis to be used, the thickness may vary from place to place in one sheetand two sheets of supposedly the same guage may have 'diiferentthicknesses due to manufacturing tolerances.

Where the sheet is undersize, the project-ions 16 will still engagebehind the sheet and prevent the sleeve from coming out when the screwis being inserted. Where the sheet is oversize, the projections 16 maynot pass right through the hole 13 and the noses 18 will be trappedinside the hole 13 instead of engaging the surface 2 However, due to theparticular formation of the projections they will exert a grip upon thewall of the hole 13 and any tendency for the sleeve to withdraw, willonly serve to increase this grip so that the projections still functionto prevent withdrawal even though the sheet is oversize.

In the above described embodiment, the sleeve has a passage 21 whichextends right through from end to end but in certain cases, for examplewhere a liquid tight seal is required, it would be advantageous toprovide the sleeve with a closed end so that it has a blind hole thereinand when applied as a fastening in a manner as above described, theclosed end of the sleeve would result in a complete seal being formedaround the end of the screw remote from its head. Such an applicationwould be of advantage when applying the fastening device to such thingsas containers containing corrosive fluid.

What I claim then is:

1. A screw fastening device comprising a sleeve of deformable material,said sleeve having an axial bore extending from one end at leastpartially to an end remote from the one end, said bore being enlarged inthe region of the one end and of smaller diameter in the region of theremote end, a flange at the one end of the sleeve, a portion ofnon-circular cross section immediately below the flange fornon-rotatable engagement in a similarly shaped hole in a member to whichthe fastening is applied, the maximum dimension of said portion ofnoncircular cross section being less than the minimum dimension of saidflange, the remaining sleeve portion from the non-circular portion tothe remote end of the sleeve-being of circular cross section of lessarea than that of an end face of the non-circular portion adjacent thecircular portion, the diameter of said circular sleeve portion being nogreater than the minimum dimension of the non-circular portion, thecircular sleeve portion wall immediately adjacent the non-circularportion being thin compared to the circular sleeve portion wall attheremote end, and a plurality of circumferentially spaced lockingprojections integral with the non-circular portion, each lockingprojection having a stern extending from said end face of thenon-circular portion towards the remote end, the stem being parallel tothe sleeve axis and spaced from the thin wall of the circular sleeveportion, and a nose projecting radially outwardly from the outer end ofthe stem beyond the periphery of the non-circular portion.

2. A screw fastening device comprising a sleeve of deformable material,said sleeve having an axial bore extending from one end at leastpartially to an end remote from the one end, said bore being enlarged inthe region of the one end and of smaller diameter in the region of theremote end, a flange at the one end of the sleeve, a portion of squarecross section immediately below the flange for non-rotatable engagementin a similarly shaped hole in a member to which the fastening isapplied, the maximum dimension of said portion of square cross sectionbeing less than the minimum dimension of said flange, the remainingsleeve portion from the square portion to the remote end of the sleevebeing of circular cross section of less area than that of an end face ofthe square portion adjacent the circular portion, the diameter of saidcircular sleeve portion being no greater than the minimum dimension ofthe non-circular portion, the circular sleeve portion wall immediatelyadjacent the square portion being thin compared to the circular sleeveportion wall at the remote end, and two locking projections integralwith the square portion, one disposed in each of two opposed corners ofthe square portion, each locking projection having a stem extending fromthe square portion towards the remote end, the stern being parallel tothe sleeve axis and spaced from the thin wall of the circular sleeveportion, and a nose projecting radially outwardly from the outer end ofthe stern beyond the periphery of the square portion, the face of thenose towards the remote end being inclined in respect to the sleeve axisand the inclined surfaces of the two noses converging towards said axisin a direction away from the flange.

(References on following page) References Cited in the file of thispatent UNITED STATES PATENTS Tinnerman Aug. 5, 1952 6 Rapata May 27,1958 Edwards May 29, 1959 Shamban et a1 Nov. 17, 1959 Ahlgren July 26,1960 Bratton Dec. 26, 1961 Cochran Aug. 21, 1962

1. A SCREW FASTENING DEVICE COMPRISING A SLEEVE OF DEFORMABLE MATERIAL,SAID SLEEVE HAVING AN AXIAL BORE EXTENDING FROM ONE END AT LEASTPARTIALLY TO AN END REMOTE FROM THE ONE END, SAID BORE BEING ENLARGED INTHE REGION OF THE ONE END AND OF SMALLER DIAMETER IN THE REGION OF THEREMOTE END, A FLANGE AT THE ONE END OF THE SLEEVE, A PORTION OFNON-CIRCULAR CROSS SECTION IMMEDIATELY BELOW THE FLANGE FORNON-ROTATABLE ENGAGEMENT IN A SIMILARLY SHAPED HOLE IN A MEMBER TO WHICHTHE FASTENING IS APPLIED, THE MAXIMUM DIMENSION OF SAID PORTION OFNONCIRCULAR CROSS SECTION BEING LESS THAN THE MINIMUM DIMENSION OF SAIDFLANGE, THE REMAINING SLEEVE PORTION FROM THE NON-CIRCULAR PORTION TOTHE REMOTE END OF THE SLEEVE BEING OF CIRCULAR CROSS SECTION OF LESSAREA THAN THAT OF AN END FACE OF THE NON-CIRCULAR PORTION ADJACENT THECIRCULAR PORTION, THE DIAMETER OF SAID CIRCULAR SLEEVE PORTION BEING NOGREATER THAN THE MINIMUM DIMENSION OF THE NON-CIRCULAR PORTION, THECIRCULAR SLEEVE PORTION WALL IMMEDIATELY ADJACENT THE NON-CIRCULARPORTION BEING THIN COMPARED TO THE CIRCULAR SLEEVE PORTION WALL AT THEREMOTE END, AND A PLURALITY OF CIRCUMFERENTIALLY SPACED LOCKINGPROJECTIONS INTEGRAL WITH THE NON-CIRCULAR PORTION, EACH LOCKINGPROJECTION HAVING A STEM EXTENDING FROM SAID END FACE OF THENON-CIRCULAR PORTION TOWARDS THE REMOTE END, THE STEM BEING PARALLEL TOTHE SLEEVE AXIS AND SPACED FROM THE THIN WALL OF THE CIRCULAR SLEEVEPORTION, AND A NOSE PROJECTING RADIALLY OUTWARDLY FROM THE OUTER END OFTHE STEM BEYOND THE PERIPHERY OF THE NON-CIRCULAR PORTION.